A variety of communication and sensing systems with high sensitivity receivers are known. However, these communication and sensing systems often struggle to operate with high sensitivity and reliability while operating in an environment with high power interferers. One of the goals of this invention is to offer an economical retrofit solution to these communication and sensing systems to null these high power interferers dynamically while maintaining their high sensitivity receiver capabilities and substantially increasing their reliability.
Many critical receivers such as Global Positioning Satellite (GPS) receivers, and radio frequency (RF) communication, radar, satellite communications, electronic surveillance, and many other receivers, operate with high sensitivity to detect and process signals from large distances. However, this inherent sensitivity also makes them less resilient to damage by high power sources in the environment. In the case of military systems, these high power interferers can be jammers or electronic attack platforms intended to deny the mission of one of the aforementioned receivers. For many other applications these interferers are often neighboring or adjacent transmitters such as high power radar systems which are unintentionally transmitting power in the direction of a sensitive receiver. While techniques exist to mitigate this interference, none provide a solution which allows existing sensitive receivers to continue operating while in the presence of an undesired high power interferer.
One of the goals of this invention is to enable a retrofit radome technology which can autonomously blank or null a sector or sectors in the radiation pattern of antennas and apertures connected to a sensitive receiver to deny high power radiation emitted towards these antennas from damaging sensitive electronics in the receiver and thus allow the receiver to continue operating without damage.
Several technologies exist for mitigating high power interference, however none of these can adaptively steer nulls in the radiation pattern of an existing receiver without replacing the existing antenna and do not provide a mechanism for the receiver to continue normal operation at unnulled angles while under the illumination of a high power source. Some of these technologies include the use of a conventional diode limiter which prevents damage to receivers when illuminated by high power radiation sources by shorting the input of the receiver. However, this approach also prevents the receiver from receiving incoming signals while exposed to the external high power source.
Other techniques such as reconfigurable antennas offer low power methods for adaptively steering nulls in the radiation pattern of a receiver to mitigate interference, but these technologies do not have an integrated capability to sense the bearing of incoming high power threats while protecting the receiver at the same time and do not have any tuning mechanism robust enough to null the radiation pattern of the receiver at very high power levels.
Some techniques offer replacement designs requiring a new receiver. One such example is the use of an array of electronically controlled parasitic scatters coupled to a central feed antenna to selectively null different sectors in the radiation pattern of the antenna by switching binary loads on or off at the parasitic scatters. These techniques are not retrofit solutions and do not have any means to identify the bearing of a high power interferer while preventing damage to the receiver connected to the antenna while doing so.
Some techniques try to mitigate the effect of interferers by notching the portion of the frequency spectrum on which the interferer is operating. However, this technology does not provide a means of mitigating interferers which are in-band or operating at the same frequency as the receiver.
Hence there is an urgent need in communication and sensing systems that operate with high sensitivity to develop a radome that can be placed over the existing antennas which can autonomously identify the bearing of a high power threat and subsequently null said threat without replacing the existing antenna. Furthermore, there is an urgent need to dynamically locate the bearing of high power interferers while simultaneously protecting sensitive electronics in the receiver from damage and to place a null in the direction of the interferer, while allowing the receiver to continue operating normally at other angles.